package store

import (
	"database/sql"
	"fmt"

	_ "github.com/jackc/pgx/v4/stdlib"
	"github.uio.no/torjus/apiary/models"
)

const DBSchema = `
CREATE TABLE IF NOT EXISTS login_attempts(
	id serial PRIMARY KEY,
	date timestamptz,
	remote_ip inet,
	username text,
	password text,
	client_version text,
	connection_uuid uuid,
	country varchar(2)
);
`

type PostgresStore struct {
	db *sql.DB
}

func NewPostgresStore(dsn string) (*PostgresStore, error) {
	db, err := sql.Open("pgx", dsn)
	if err != nil {
		return nil, err
	}
	rs := &PostgresStore{
		db: db,
	}
	return rs, nil
}

func (s *PostgresStore) InitDB() error {
	_, err := s.db.Exec(DBSchema)
	return err
}

func (s *PostgresStore) AddAttempt(l *models.LoginAttempt) error {
	stmt := `INSERT INTO 
login_attempts(date, remote_ip, username, password, client_version, connection_uuid, country)
VALUES ($1, $2, $3, $4, $5, $6, $7)
RETURNING id;`
	tx, err := s.db.Begin()
	if err != nil {
		return err
	}
	defer tx.Rollback()

	var id int
	if err := tx.QueryRow(stmt, l.Date, l.RemoteIP.String(), l.Username, l.Password, l.SSHClientVersion, l.ConnectionUUID, l.Country).Scan(&id); err != nil {
		return err
	}
	l.ID = id
	return tx.Commit()
}

func (s *PostgresStore) All() ([]models.LoginAttempt, error) {
	stmt := `SELECT date, remote_ip, username, password, client_version, connection_uuid, country FROM login_attempts`

	rows, err := s.db.Query(stmt)
	if err != nil {
		return nil, err
	}
	defer rows.Close()

	var attempts []models.LoginAttempt
	for rows.Next() {
		var a models.LoginAttempt
		if err := rows.Scan(&a.Date, &a.RemoteIP, &a.Username, &a.Password, &a.SSHClientVersion, &a.SSHClientVersion, &a.Country); err != nil {
			return nil, err
		}
		attempts = append(attempts, a)
	}

	return attempts, nil
}

func (s *PostgresStore) Stats(statType LoginStats, limit int) ([]StatsResult, error) {
	var stmt string

	if statType == LoginStatsTotals {
		return s.statsTotal(limit)
	}

	switch statType {
	case LoginStatsCountry:
		stmt = `select country, count(country) from login_attempts order by count desc`
	case LoginStatsIP:
		stmt = `select remote_ip, count(remote_ip) from login_attempts order by count desc`
	case LoginStatsPasswords:
		stmt = `select password, count(password) from login_attempts order by count desc`
	case LoginStatsUsername:
		stmt = `select username, count(username) from login_attempts order by count desc`
	}

	if limit > 0 {
		stmt = fmt.Sprintf("%s limit %d", stmt, limit)
	}
	rows, err := s.db.Query(stmt)
	if err != nil {
		return nil, err
	}
	defer rows.Close()

	var results []StatsResult
	for rows.Next() {
		var r StatsResult

		if err := rows.Scan(&r.Name, &r.Count); err != nil {
			return nil, err
		}
		results = append(results, r)
	}

	return results, nil
}

func (s *PostgresStore) statsTotal(limit int) ([]StatsResult, error) {
	uniquePasswordStmt := `select count(*) from (select distinct password from login_attempts) as temp`
	uniqueUsernameStmt := `select count(*) from (select distinct username from login_attempts) as temp`
	uniqueIPStmt := `select count(*) from (select distinct remote_ip from login_attempts) as temp`
	uniqueCountryStmt := `select count(*) from (select distinct country from login_attempts) as temp`
	attemptsCountStmt := `select count(1) from login_attempts`

	var uniquePasswordsCount int
	if err := s.db.QueryRow(uniquePasswordStmt).Scan(&uniquePasswordsCount); err != nil {
		return nil, err
	}
	var uniqueUsernameCount int
	if err := s.db.QueryRow(uniqueUsernameStmt).Scan(&uniqueUsernameCount); err != nil {
		return nil, err
	}
	var uniqueIPCount int
	if err := s.db.QueryRow(uniqueIPStmt).Scan(&uniqueIPCount); err != nil {
		return nil, err
	}
	var uniqueCountryCount int
	if err := s.db.QueryRow(uniqueCountryStmt).Scan(&uniqueCountryCount); err != nil {
		return nil, err
	}
	var attemptsCount int
	if err := s.db.QueryRow(attemptsCountStmt).Scan(&attemptsCount); err != nil {
		return nil, err
	}
	return []StatsResult{
		{Name: "UniquePasswords", Count: uniquePasswordsCount},
		{Name: "UniqueUsernames", Count: uniqueUsernameCount},
		{Name: "UniqueIPs", Count: uniqueIPCount},
		{Name: "UniqueCountries", Count: uniqueCountryCount},
		{Name: "TotalLoginAttempts", Count: attemptsCount},
	}, nil
}